Should note: "stacked" like social media karma monotonically increases - the aggregate value of your participation on the site. "sats" is your spendable balance which goes up when you get upvotes or fund your account and goes down when you withdrawal or spend 1 sat upvoting, commenting, or posting. 

Another way to think about it: it's the number of sats you've earned in aggregate from the birth of your account onward. It's like karma on reddit/hacker news but you can withdrawal it and buy things with it or exchange it for another currency.

k00b

Sats you've earned (aka stacked in bitcoiner terms) on the site. You commented twice. I liked both comments. You have stacked 2 sats.